Methods of sealing plastic components together are widely used in the packaging industry. The current methods used to seal plastic components together include ultrasonic sealing and impulse sealing. Both ultrasonic sealing and impulse sealing require that two surfaces be clamped together in order for the sealing process to occur.
The ultrasonic sealing and impulse sealing processes have limited application when used to seal the tops of containers where a full 360-degree seal is desired. Their limited application is due to the requirement that the two surfaces must be clamped together. In order to create a seal around the periphery of a container, a container closure member or plug would have to be clamped to the container sidewall continuously around the entire periphery of the container sidewall. In order to clamp a plug to the container sidewall, an inner backup tool would have to be placed inside of the plug opening and an outer clamping tool would have to be placed outside of the container sidewall.
The inner backup tool placed inside of the plug opening would have to be split in order to get inside of the plug opening while not dislodging the plug from its position within the container sidewall. Once the split backup tool is within the plug opening, it would have to expand to a diameter approximately equal to the inside diameter of the plug. This expansion of the inner split backup tool would create gaps between its segments thereby leaving areas of the plug and container sidewall which do not get clamped together and are not sealed. Therefore, a full 360-degree seal is not formed.
Accordingly, a need exists for a method of sealing plastic containers in which a full 360-degree seal can be formed.